Red Bull’s cars have been referred to the German Grand Prix stewards after the FIA’s technical delegate detected a possible breach of Formula 1’s engine mapping regulations.

Sebastian Vettel is due to start today’s race at Hockenheim from second on the grid, while Mark Webber qualified in third, but was relegated to eighth after being forced to change his car’s gearbox.

Red Bull have been accused of using illegal engine mapping (Getty Images)

Should the stewards conclude Red Bull have broken the rules, the pair could be made to start from the back of the grid, although they may be allowed to appeal and maintain their positions, ahead of a final decision being made after the race.

Jo Bauer, of motor racing’s governing body the FIA, contacted all the teams on Sunday to inform them of his concerns.

He revealed he had identified an issue with Red Bull’s engine base torque map that may constitute a breach of the sport’s technical regulations, and explained the set-up ‘will artificially alter the aerodynamic characteristics of both cars’.

Any grid penalty or post-race disqualification would have a significant impact on the drivers’ championship, as Webber and Vettel are currently second and third behind Ferrari’s Fernando Alonso.